The use of a pump particularly in the handling of food and dairy products has always been subjected to stringent sanitary regulations and as a result thereof the pump must be capable of withstanding repeated and thorough washing cycles wherein strong and/or high temperature cleaning solutions are utilized. Heretofore in order to meet such regulations the pumps were designed so that they could readily be disassembled. Such a capability, however, involved a time consuming, awkward, and frustrating manual operation. With the introduction of the clean-in-place concept, partial disassembly of the group was oftentimes still required, and/or in certain instances the pump was required to be of complex and costly construction. Furthermore, because of the high temperatures to which the pump components were normally subjected during the cleaning cycle, certain of the components would expand or swell thereby causing excessive wear to occur during the cleaning cycle, or when the pump would run dry prior to the fluid reaching the pump from a remote location, or in some instances when the pump resumed its pumping operation. In still other instances, during the clean-in-place cycle, the pump produced a substantial pressure drop within the line in which the pump was connected thereby adversely affecting proper cleaning of other equipment connected in the line.